// 接口:是一种能力,一种约束
(() => {
  // 定义一个接口
  interface Iperson {
    firstName: string,
    lastname: string
  }

  function showFullName(person: Iperson): string {
    return person.firstName + '_' + person.lastname
  }
  const person = {
    firstName: '周',
    lastname: '张恒'
  }
  console.log(showFullName(person));

})()